VIENNA - Iran is refusing to significantly cut the number of centrifuges it intends to keep to produce nuclear fuel, making it hard to imagine a compromise at this week's talks with six powers, Western and Iranian officials said on Wednesday.

The remarks from diplomats close to the talks, who spoke on condition of anonymity, came after the initial rounds of meetings in the Austrian capital between Iran and the United States, Britain, France, China, Russia plus Germany.

Perhaps the biggest hurdle to overcome, six-power diplomats said, is Iran's stance regarding its uranium-enrichment centrifuges, which one negotiator described as a "huge problem".

"The Iranians have not yet shown a willingness to reduce their centrifuges to an acceptable number, making it difficult to envision a compromise at this point that we could all live with," the negotiator told Reuters.

Another Western official close to the talks confirmed the remarks as accurate.